Finding the Fourth Proportional to 2,720.89, 4,080.78 and 772.57

Step by Step Solution

1. Step 1: Write the proportion equation
   2,720.89 : 4,080.78 = 772.57 : x
2. Step 2: Convert to fraction form
   2,720.89/4,080.78 = 772.57/x
3. Step 3: Cross multiply
   2,720.89x = 4,080.78 × 772.57
4. Step 4: Simplify right side
   2,720.89x = 3,152,688.20
5. Step 5: Solve for x
   x = 3,152,688.20/2,720.89
6. Step 6: Final answer
   x = 1,158.70